The present invention relates to a vertical roller mill for crushing or milling clinkers or blast furnace slag for use as cement material.
FIG. 1 of the accompanying drawings shows a prior art vertical roller mill, of the type disclosed in Japanese Patent Provisional Publication No. 60-12151 laid open on Jan. 22, 1985. In FIG. 1, the mill includes a rotary table 2 having an annular groove 4 formed in its upper surface 3. The table is rotated on a substantially vertical axis, and the groove 4 is located adjacent the outer periphery 5 of the table. A plurality of circumferentially spaced rollers 6 (only one shown) are supported above the table and roll in the groove 4. Material 9 being milled is located in a clearance space 8 formed between the groove 4 and the rollers. The width of the space 8 is narrowed on the radially outward side of the groove to resist the outward flow therefrom of the material 9 being milled, in order to produce efficient milling etc.
It is a general object of this invention to provide a vertical roller mill, which is improved in its capability to retain material being milled in the groove between the rotary table and the rollers for a relatively long time.